Having just got a nice new Trek hybrid for computing, I decided to go for a wireless computer instead of the wired one I had on my old bike.

I bought the Halfords 9 function model, and diligently followed the setup instructions. At first it seemed to work but the first time I rode it, it didn't start registering for about half a mile. The next time it took about a mile.

I've just tried resetting it all from scratch (Including resetting the computer itself), but now I can only get it to register if I hold the activation switch in, spin the wheel and hold the computer about 3 inches away from the transmitter!!

I think some of the problem may be the positioning of the transmitter. No matter how I fit it, the transmitter either points through the wheel or the brake blocks. If I adjust it, then it's too far from the spoke mounted magnet.

Does anyone have any ideas before I take it back to Halfords for a refund? Am I doing something wrong or does it sound like a faulty unit?

Did batteries come with the unit? It could be that the batteries need replacing. Mine starts playing up in the same way when the batteries are running low.

Yes - thought about that but guess I assumed they should be OK. I'll try changing them and see what happens.

Just run down the road to get some new batteries (Boots - No, Wooworths - No, Halfords - Yes. Surprise surprise)

Anyway, seems to work now. Just changed the transmitter battery. I think I'd rather go back to the batteries not included days. At least you know they're good when you buy them yourself.

On a related note - how long do they tend to last in these wireless computers?

cracking glad its sorted. And the 12v battery in my transmitter lasts a good year or so before its needs replacing.

The 2032 in the receiver/computer bit a bit more regularly, I'd hazard a guess at 2 or three times a year.